TCPMv2: Handle unexpected msgs received during Port Discovery
TCPMv2: Handle unexpected msgs received during Port Discovery

During a port discovery, unexpected messages such as SRC_CAPs
and Not_Supported are handled by the Src.Attached or Snk.Attached
state and the port discovery process is terminated.

BUG=chromium:1027252
BRANCH=none
TEST=make -j buildall
	Manual Test:
	Used an Anker charger to verify that Not Supported
	messages are handle correctly during a Port Discovery.
	Total Phase output:
		Source:DFP, Source_Cap
		Sink:UFP,   GoodCRC
		Sink:UFP,   Request
		Source:DFP, GoodCRC
		Source:DFP, Accept
		Sink:UFP,   GoodCRC
		Source:DFP, PS_RDY
		Sink:UFP,   GoodCRC
		Sink:UFP,   VDM:DiscIdentity
		Source:DFP, GoodCRC
		Source:DFP, Not_Supported
		Sink:UFP,   GoodCRC

Change-Id: I48db149c0c59affe6aad49b8b1bcfb6dc3656142
Signed-off-by: Sam Hurst <500b4cddcd66abe3fe333e92c4c95d7f41e62e4e@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1928793
Reviewed-by: Denis Brockus <6b21e8190fb5e373363fb95271367073a16474ef@chromium.org>
Reviewed-by: Jett Rink <9d4aef0593e6843318d99df31597fb6153b89787@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec